<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>gengxin</title>
    <script src="../../前端开发/vue.js"></script>
</head>
<body>
    <div id="app">
        <div v-if="isShow" ref="self">test</div>
        <button @click="isShow=!isShow">更新</button>

    </div>
    <script>
        var vm = new Vue({
            el: '#app',
            data: { isShow: false },
            beforeUpdate () {
                console.log('更新之前')
                console.log(this.$refs.self)
            },
            updated () {
                console.log('更新之后')
                console.log(this.$refs.self)

            }
        })
    </script>
    
</body>
</html>